Immune response and survival of Circulifer haematoceps to Spiroplasma citri infection requires expression of the gene hexamerin. Issue 1 (January 2016)

• Record Type: Journal Article
• Authors: Eliautout, Rémi; Dubrana, Marie-Pierre; Vincent-Monégat, Carole; Vallier, Agnès; Braquart-Varnier, Christine; Poirié, Marylène; Saillard, Colette; Heddi, Abdelaziz; Arricau-Bouvery, Nathalie
• Is Part Of: Developmental and comparative immunology. Volume 54:Issue 1(2016)
• Page Start: 7
• Page End: 19
• Publication Date: 2016-01
• Subjects: Hemipteran innate immunity -- Spiroplasma -- Immune cells -- Hexamerin -- Phenoloxidase activity -- RNAi; AMP antimicrobial peptide -- CFU colony-forming unit -- dsRNA double-stranded RNA -- EST expressed sequence tag -- GFP green fluorescent protein -- GNBP gram negative binding protein -- HLS haemocyte lysate supernatant -- IgG and IgM immunoglobulin G and M -- IL-1 interleukin 1 -- IMD immune deficiency -- LPS lipopolysaccharide -- MAMP microbial-associated molecular patterns -- NSRO Drosophila nebulosa sex ratio organism -- PG peptidoglycans -- PGRPs peptidoglycan recognition proteins -- PO phenoloxidase -- PTU phenylthiourea -- RNAi RNA interference -- RNA-seq RNA sequencing -- ScARPs S. citri adhesion-related proteins -- SSH suppression substractive hybridization -- TNF tumour necrosis factor; Immunology -- Periodicals; Developmental immunology -- Periodicals; 616.079
• DOI: 10.1016/j.dci.2015.08.007
• Languages: English
• ISSNs: 0145-305X

Abstract

Abstract: Spiroplasma citri is a cell wall-less bacterium that infects plants. It is transmitted by the leafhopper Circulifer haematoceps, which hosts this bacterium in the haemocel and insect tissues. Bacterial factors involved in spiroplasma colonization of the insect host have been identified, but the immune response of the leafhopper to S. citri infection remains unknown. In this study, we showed that C. haematoceps activates both humoral and cellular immune responses when challenged with bacteria. When infected by S. citri, C. haematoceps displayed a specific immune response, evidenced by activation of phagocytosis and upregulation of a gene encoding the protein hexamerin. S. citri infection also resulted in decreased phenoloxidase-like activity. Inhibition of hexamerin by RNA interference resulted in a significant reduction in phenoloxidase-like activity and increased mortality of infected leafhoppers. Therefore, the gene hexamerin is involved in S. citri control by interfering with insect phenoloxidase activity. Highlights: Spiroplasma citri induced a specific immune response compared to Escherichia coli and Micrococcus luteus . Activation of phagocytosis is observed in Circulifer haematoceps after S. citri infection. S. citri promotes a continuous phenoloxydase activity decrease in insect hemolymph. We succeed in using RNA interference to inhibit the transcription of hexamerin gene. Hexamerin is required for full PO activity and insect surviving to S. citri infection.